Refrigeration system



Aug. 4, 1936.

J. W. GILBERT REFRIGERATION SYSTEM 2 Sheets-Sheet 2 Filed Oct. 6, 1954WQN o 1% N. W \\\\A EN kkmfikwm .v MN. WMN \SQQ A v UN @1134 I k Illllfiw z Patented Aug. 4, 1936 PATENT OFFICE REFRIGERATION SYSTEM James W.Gilbert, .Johnstown, Pa., assignor of one-half to Ernest F. Walker,Johnstown, Pa.

Application October 6, 1934, Serial No. 747,172

7 Claims.

This invention relates to improvements in the art of mechanicalrefrigeration, primarily designed for refrigeration systems in which acooling medium or refrigerant is circulated from a 5 common sourcethrough a multiple series of cooling coils or units in a singleinstallation.

In the improved types, such cooling systems generally include acompressor delivering compressed refrigerant to a condenser and a liquid10 receiver, from whence a supply conduit or line delivers the liquidrefrigerant through connecting branch lines to each of the separatedindependent cooling coils or units. Return lines from said unitscommunicate with the compressor 15 through a common return conduit toprovide a closed system.

Each of the several cooling units or refrigerators has usuallyassociated therewith an expansion or float valve and an automaticregulat- 20 ing or two-temperature control valve combining a to providethe desired individual temperatures in the several units.

In the operation of these multiple coil or freezing unit installations,both in the domestic and 25 the commercial fields, considerabledifliculty has been experienced in maintaining stable temperatures inthe various units. While the system may operate satisfactorily so longas the compressor is operating, when the compressor is in- 30 activeboiling frequently occurs in the suction or return lines, flooding thesame with wet gas, and causing frozen lines and a frozen compressor. Thecompressor running time becomes excessive, tubing collapses, flare unitsbreak, and 35 the system is ineffective until repaired. Likewise, thepressure of wet gas in the return line producesfoaming of the oil in thecompressor, causing damage to valves and other working parts of thesystem.

40 I have discovered that these highly objectionable reactions andcostly interruptions of service result from back-pressure set up uponthe warming up of the coil and line which absorbs the greatest amount ofheat, which back-pressures 45 are transmitted to the coils and lines ofone or more units operating at relatively lower pressures. This higherpressure refrigerant is promptly absorbed and condensed in the lowpressure coil or coils, thereby raising the liquid 50 levels therein andprematurely raising the pressures and temperatures above normal. Whenthe compressor starts, the excessive amounts of refrigerant contained insaid coils gushes down the suction lines flooding the same with wet gasand causing freezing, etc. as stated above.

When this action takes place, all means heretofore employed fortemperature or pressure control become ineffective until the entiresystem is again pumped down and each individual unit acquires itspredetermined pressure and the resulting temperature.

It is a prime object of my invention to provide, particularly in amultiple refrigeration system, individual automatically operable controlmeans for preventing the back flow or reverse circulation of refrigerantbetween the coils and lines of two or more separate units of the systemoperating at different pressures and temperatures, operable inconnection with the ever present entrained oil circulating with therefrigerant to form an eflicient barrier to said circulation.

I further contemplate a simple and efilcient control means readilyadaptable to present installations, and a control means applied in closeproximity to the evaporator or cooling, coil and on the return sidethereof, to utilize the semisolid or congealed oil discharged therefromas a sealing medium. v

My invention may be more clearly understood from the followingdescription taken in connection with the accompanying drawings, wherein:

Fig. 1 is a diagrammatic view of a multiple refrigeration installation,showing the application of my invention thereto;

Fig. 2, an enlarged longitudinal vertical sectional view of one of theevaporators and the control means of the present invention; and

Fig. 3, a detail section taken on the line III III of- Fig. 2.

For the purpose of illustration, I have shown herein a multipleinstallation including a plurality of cooling units or refrigeratorsdesired to be operated at different temperatures, but it will 'beunderstood that my invention is not to be limited thereto, as the samemay be embodied in any mechanical refrigeration system whether it be amultiple installation or a single unit.

Referring to the drawings, 5 designates a compressor of thereciprocating type driven by a 40 motor 6 to compress and discharge acooling medium or refrigerant, as for example, sulphur dioxide, into acondenser l and thence into a liquid receiver or tank 8.

The refrigerant in liquid form is passed from the receiver 8 through apipe or line 9 to the cooling units mounted in compartments orrefrigerator cabinets A, B, C and D through branch lines 9a, 9b, 9c, and9d respectively. For the purpose of simplicity, the various elements inthe individual compartment systems are given reference numerals havingletters corresponding to the compartment designation above, and but oneof said compartment systems is described in detail, the others havinglike elements, as will be readily seen and understood. Thus, incompartment A, the branch line So communicates with an evaporator orboiler Illa through a shut-off valve I la and a float valve controlcomprising a needle valve l2a operable absorption surface of the unit.The gaseous refrigerant in the evaporator,

produced by the low pressure expansion of the refrigerant, upon theabsorption of heat passes outwardly from the said evaporator through areturn or suction line its having a shut-off valve l6a. The lines lBa,lib, I50, and lid communicate with a common return line I! connectingwith the suction side of the compressor 5. Ha, Ilb, lie, and liddesignate control valves in the return or suction lines of therespective compartments, said valves being of standard construction andoperating by reason of either pressure or temperature variations tocontrol the flow of refrigerant in said lines to the compressor I. Thesevalves are generally designated in the art as an automatic regulatingvalve or a twotemperature snap-action valve.

Electrically connected in circuit with the m0- tor 6 is an automaticpressure control switch l8 having connection .with the suction anddischarge sides of the compressor 5 by pipes l9 and 20 respectively,said pipes having bellows operable by pressure variations to open andclose the motor circuit at predetermined pressures or i temperatures in;the system. 2| refers to the circuit connections with a suitable sourceof electricity or power line 22 through a main switch 23.

Assuming the float and automatic regulating valves to be adjusted toprovide different pressures in the several units or compartments, as isthe case in certain commercial installations, the system is charged withrefrigerant and the control switch I 8 adjusted to regulate the cutinand cut-out of the compressor at predetermined pressures, saidadjustment generally being in accordance with the temperature variationpermitted in the compartment desired to be maintained at the lowesttemperature of the entire installation.

temperatures of the refrigerant in the other units, and when thecompressor is cut-in by the control switch la, the same must necessarilyoperate for an extended period of time in order to again pump down allof said units.

In addition, this back or inter-flow between units raises theirtemperatures and pressures to such a degree that boiling occurs in theevaporators and suction lines, flooding said lines with wet gaseousrefrigerant and eventuating in frozen lines and freezing of therefrigerant in the compressor.

Likewise, in such refrigeration apparatus, the suction lines I 5, I511,lib, lie, and lid are generally of considerable length, eitherindividually or collectively, depending upon the location of thecompressor. relatively to the cooling units. Frequently in largeinstallations, the compressor is placed in a basement or far removedroom, necessitating long suction lines within the buildi s. V

In such installations, it not infrequently happens that the said suctionlines pass through tion line to the evaporator.

substantially warm regions which have a similar effect to that justdescribed, causing a backpressure flow of refrigerant to the evaporatorsand interrupting the regularity of the cycle and the desiredtemperatures.

As is general practice, oil is present in the system, being originallyintroduced to the lower crank case of the compressor 5, which oil isentrained at compression and passes through the system with andsuspended in the refrigerant in the form of globules or particles, saidoil supplying lubrication for the parts of the entire system. During theabove-mentioned boiling, this oil foams and its lubrication value isdestroyed, resulting in injury to the moving parts of the system.

To obviate these difliciilties and to provide for stable conditions inthe system and the several individual units, I have providedautomatically operable means in the form of a control valve, 20

tions, but I prefer to provide the same of the 25 type having a hollowbody 24 enclosing a reciprocable stem valve 25 on a seat 26 at the endof said body next to the evaporator or boiler I001. 21 designates aspring normally seating said valve against any return flow from the suc-30 Standard flare connections." connect the valve in the suction line15a.

With the valve E so positioned, it is readily seen that any back orinterflow between units 3 is prevented, the said valves acting asautomatic checks to permit flow of refrigerant in one direction only, i.e., to the compressor from the evaporator. Hence, in operation, thevarious temperatures or pressures in the several units or compartmentsare maintained within their respective predetermined ranges withoutappreciable variation.

It is well known in the art that considerable difficulty is encounteredin the sealing of connections or the seating of valves, due to the greattendency of the standard refrigerants to penetrate and leak.- Failure ofthe valves E to seat perfectly will render the same inefllcient.

In order to insure proper seating or closing of the valves E, I preferto position said valves in the suction lines-of the respective unitsadjacent to or as close as possible to the evaporator-s. The oilparticles entrained by the, refrigerant form slugs or globules, whichlie along the upper surfacev of the liquid refrigerant in theevaporators, as indicated in Fig. 2, in a semi-solid or congealed state,due'to the lowtemperatures.

Said slugsare" carried by the expanded refrigerant from the evaporatorsimmediately to the control valves E, where they form sealing filmsaround the valves 25- and their seats 26, thus providingrefrigerant-tight seals, preventing any leakage.

In addition, the major portion of the oil passes directly through thevalves E to the com-' pressor for re-circulation. There is no trappingof the oil when-the valves are located next to the evaporator because ofsaid congealed condition, the particles thereof being readily carried insuspension by the moving refrigerant. The oil in a less viscous state,as would be the case at a point further along in the lower and warmerregions of the suction lines, would not provide an eflicient seal and,likewise, should the valves'E be placed at such lower regions, the oilin a liquid state would be trapped in the lowermost points of thevalves.

Also, by positioning the valves E next to the evaporator, and acting asthey do to prevent back-flow to said evaporators from the suction lines,any increase of pressures in the suction lines due to heating up asbefore, will have no effect upon the evaporators, since the valvescompletely prevent any return communication with said evaporators.

A mechanical refrigeration system equipped with my invention will beentirely stable and uniform in its operations. In a multiple installation such as that shown and described, various temperatures aremaintained as desired in the separate cabinets or compartments/byadjusting the expansion valves at the evaporators, and setting theautomatic or two-temperature control valves in the suction lines.

The compressor control through its switch I8 is also aided by theprovision of the valves E due to the fact that only the change inpressure within any individual evaporator acts upon said switch, withoutthe influence of irregular variations of back-pressure as has heretoforebeen experienced. Hence, the compressor operates only when needed tore-service one or more units which have become warm through use, and theactual running time of the compressor is thereby materially decreasedover present practice.

This accurate control of ,pressures and temperature is also accomplishedby the use of my invention in apartment house installations where aplurality of units are operated at the same temperature, and willeffectively protect such system against variations caused by unequalapplication of the load upon the individual units. It may be said thateach unit provided with a valve E in the manner described will havecomplete individual control of the switch l8, thereby operating asemciently as a single unit system.

My invention may be applied in a like manner to a single unit systemwith equal advantage. It is well known that the suction and dischargevalves of the compressor eventually leak, thereby causing back-pressuresin the return or suction line, which, when transmitted to theevaporator, cause the compressor to run longer and more frequently thanis necessary. By incorporating my invention in the manner set forthherein, any back-flow or pressure due to leaking valves will have noeffect upon the cooling cycle of the unit, since the same cannot enterthe evaporator.

I claim:

1. In a refrigeration system comprising a closed system including acompressor, a condenser and a single evaporator, a liquid fluid linefrom the condenser to the evaporator, a suction line connecting saidevaporator and the compressor, and automatically operable means disposedin the suction line associated with the evaporator preventing a backflow of refrigerant created between the compressor and the evaporator tothe evaporator.

2. In a refrigeration system comprising a closed system including acompressor, a condenser and a single evaporator, a liquid fluid linefrom the condenser to the evaporator, a suction line connecting saidevaporator and the compressor, and an automatically operable valvedisposed in the suction line, a part of said suction linerigidlyconnecting the body of said valve to the casing of said evaporatorpreventing a back flow of refrigerant created between the compressor andthe evaporator to the evaporator. 5

3. In a refrigerationsystem comprising a closed system including acompressor, a condenser and an evaporator in which a suitablerefrigerant mixed with lubricating oil is employed, a suction lineconnecting said evaporator and the compressor, and an automaticallyoperable spring-seated valve disposed in the suction line associatedwith said evaporator preventing a back flow of refrigerant to theevaporator, said valve receiving the oil as it passes from theevaporator in a congealed state to effect a seal between said valve andits seat.

4. In a refrigeration system comprising a closed system including acompressor, a condenser and a plurality of evaporators, a fluid ingvalves adjacent the suction line, and independent automatically operablemeans associated with each evaporator and disposed in the suction lineassociated with each evaporator for preventing a return flow ofrefrigerant to any 1airlid all of the evaporators from said suction 5.In a multiple refrigeration system compris= ing a plurality of coolingunits having individual evaporators connected with a compressor andcondenser for the circulation of a refrigerant, suction lines from eachof said evaporators connecting with the suction side of said compressor,automatically operable valves disposed in said suction lines adjacenteach evaporator for preventing a back and interflow of refrigerant toand between any and all of the said evaporators by reason of backpressures in the suction lines, and as and for the purpose described.

6. In a multiple refrigeration system compris= ing a plurality ofcooling units havingindividual evaporators connected with a compressorand condenser for the circulation of a refrigerant, individual suctionlines from each of said evaporators leading to a common suction line,the latter connecting with the suction side of said compressor,regulating valves in the common suction line, and automatically operablevalves disposed in the individual suction lines associated with theevaporators for preventing a back and interflow of refrigerant to andbetween any and all of the said evaporators.

7. A multiple refrigeration system comprising a plurality of coolingunits each. having an evaporator. a compressor and condenser with sowhich each evaporator is operatively' connected for circulatingrefrigerant, suction lines from each of said evaporators connected tothe suction side of said compressor, automatically operable valvesdisposed one in each suction line, 65 a part of each suction linerigidly connecting the valve thereof to the associated evaporator toprevent a back and interflow of refrigerant to and between saidevaporators.

I JAMES w. GILBERT.

